Experimental Study On Residual Bearing Capacity Of Concrete Beams With T-shape Under Different Load Ratio After Elevated Temperature

After the reinforced concrete structure is affected by fire,the performance of reinforcement and concrete materials will be degraded,and the bearing capacity will be reduced,which will affect the safety and durability of the structure.It is necessary to study the residual mechanical properties of reinforced concrete structure after high temperature.In this paper,a total of 10 Reinforced Concrete beams with T-shape with the same reinforcement are designed.One of the beams is used as a comparison,without fire test,and the other nine beams are tested in time limited fire test.The main research results are as follows:(1)According to the test scheme,the temperature field distribution,crack distribution,crack width and crack depth of the T-beam are obtained by the time limited fire test of the concrete T-beam.Based on the comprehensive analysis of the temperature field of concrete beams with T-shape and the relevant data of cracks,it is concluded that the larger the width and depth of cracks,the higher the section temperature of concrete beams with T-shape.(2)After the time limited fire test,9 T-beams were tested under static load according to the test plan,and the residual bearing capacity of concrete beams with T-shape was obtained.According to the analysis of the data,the longer the load ratio of concrete beams with T-shape is,the lower the residual bearing capacity is;the larger the load ratio of concrete T-beam is,the lower the residual bearing capacity is.(3)Input the relevant information of the concrete beams with T-shape into the finite element analysis software,carry out the finite element analysis,obtain the temperature field distribution of the concrete beams with T-shape under the numerical simulation,the strain data of the concrete,through the relationship between the concrete strain and the crack,the approximate width of the crack can be obtained;through the layering of the concrete,the approximate depth of the crack can be obtained.(4)Calculate the residual bearing capacity according to the previous research,comprehensively consider the influence of fire time,crack,deflection,reinforcement ratio and load,use the equivalent section method to calculate the residual bearing capacity,use the given calculation formula to calculate the residual bearing capacity,and finally get the residual bearing capacity of reinforced concrete T-beam after fire by comparing the calculation results with the test results By comparing the numerical simulation with the test results,the results meet the accuracy requirements and have certain engineering application value.